Date: Fri, 26 Oct 2007 11:44:33 -0400 From: John Baldwin <jhb@FreeBSD.org> To: Scott Long <scottl@samsco.org> Cc: src-committers@FreeBSD.org, d@delphij.net, Andrey Chernov <ache@nagual.pp.ru>, cvs-all@FreeBSD.org, Robert Watson <rwatson@FreeBSD.org>, cvs-src@FreeBSD.org Subject: Re: cvs commit: src/lib/libc/locale utf8.c Message-ID: <200710261144.34645.jhb@freebsd.org> In-Reply-To: <472120E8.90504@samsco.org> References: <200710150951.l9F9pUm7026506@repoman.freebsd.org> <20071025233536.B99770@fledge.watson.org> <472120E8.90504@samsco.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thursday 25 October 2007 07:04:08 pm Scott Long wrote: > Robert Watson wrote: > > On Thu, 25 Oct 2007, Andrey Chernov wrote: > > > >> On Thu, Oct 25, 2007 at 12:05:40PM -0700, LI Xin wrote: > >>> Well, I think the problem is not exposing a new symbol by itself, but > >>> __mb_sb_limit is being used in _ctype.h, in a form of __inline > >>> functions. Therefore, the change will break new binaries running on > >>> older systems. > >> > >> Yes. Only vice versa compatibility supported. > > > > I think the issue here is that the change occurred very quickly after > > the branch, and when users wanted to 'change gears' back to RELENG_7 > > from HEAD once it was created immediately ran into the problem. It > > seems like a useful piece of post-branch advice to developers in the > > future will be, "Please don't do things that make switching branches -- > > back or forward -- for the first few weeks after the branch is > > created". In general, I don't think we care about forward > > compatibility, but we are currently getting lots of reports because this > > is one of those few times where a lot of moving backward happens. > > > > We do care about forward compatibility within STABLE branches, as Ken > and I have discussed in side threads. But yes, forward compat between > major branches is merely desired; i.e. changes will happen, and > hopefully not for gratuitous reasons. If we care about forward compatiblity then we can't add new features to RELENG_X branches. For example, MFCing MSI to 6.x broke forward compat since a 6.3 module might call the MSI methods thus can't be used on a 6.2 kernel. AFAIK, we have _never_ promised anything wrt forward compat, only backwards ABI compat. I can agree with Robert above that during a transition time such as now it's really handy to be able to switch easily between branches, but I didn't think it was ever a concern otherwise. If we are going to change the policy for that then there's a whole bunch of crap I need to go back out of 6.x to restore compat. :-/ -- John Baldwin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200710261144.34645.jhb>